CiviCRM v3.3 introduced the extensions directory which retrieves extension listings and extension code via HTTP, and v4.3 introduced a new dashboard feed which displays news and updates retrieved from CiviCRM.org. Before v4.3.5 these were retrieved over an unencrypted channel, which raises the possibility of an attacker injecting malicious code via a "man in the middle" (MITM) attack.
In version v4.3.5+, this data will be retrieved over SSL, which will reduce the potential for malicious content injection.
